(a) Technical Field
The present invention relates to an air flow sensor chip-heating control device and method of a diesel hybrid electric vehicle, more particularly, to an air flow sensor chip-heating control device, which controls whether an air flow sensor installed in an engine intake system of the diesel hybrid electric vehicle performs a chip-heating operation.
(b) Description of the Related Art
In general, an engine of a car generates power by means of explosive power generated when a mixture gas obtained by mixing fuel and air in the atmosphere at an appropriate ratio is ignited in a combustion chamber.
In particular, fuel passing through a fuel supply device stored in a fuel tank of the car is mixed with air flowed in the engine from the exterior, and the engine repeats intake, compression, explosion and exhaust cycles as the mixture gas produced as described above is injected into cylinders of the engine. Thus, the car receives power provided through such a process.
The engine of the car can be categorized as a gasoline engine, a diesel engine, a gas engine and the like according to fuel used therein. However, air and fuel that flow in the engine through an intake system should be mixed with an appropriate air-fuel ratio in order to generate power using combustion explosive power of the engine regardless of the type of engine.
First, the amount of air that flows in the engine through the intake system should be sensed in order to set the mixture ratio of air and fuel. Thus, an air flow sensor for measuring an amount of air that flows in the engine is used in the intake system of the car.
The air flow sensor installed in the intake system of the car senses an amount of air that flows in the engine through the intake system, and enables the amount of fuel for driving the engine of the car to be determined through the sensed amount of the air.
However, an oil component is adhered to a chip built in the air flow sensor due to the countercurrent of oil vapor when the engine is stopped during driving of the car.
In order to prevent such an adhesion phenomenon, conventionally, the chip of the air flow sensor was forcibly heated every time until a main relay for transmitting electrical energy to a vehicle electric load (electrical and electronic device) is off after key-off, thereby burning and removing pollutants (oil components, dust and the like) adhered to the chip.
Specifically, if the revolutions per minute (rpm) of the engine increases to a certain value or more during driving of the engine, and the voltage of a battery is a reference value or more, the chip of the air flow sensor is heated for a certain period of time until before the main relay is off after the ignition of the engine is off in the key-off.
Meanwhile, referring to FIG. 2, in the case of a diesel hybrid electric vehicle, the vehicle enters into a hybrid operation mode several times within a one driving cycle, and the operation (driving) of the engine is stopped when the vehicle enters into the hybrid operation mode during driving of the engine. In this state, an ignition-on state is maintained for the purpose of the next engine operation, and therefore, the chip-heating function of the air flow sensor is not performed.
Accordingly, there occurs a phenomenon in which an oil component is adhered to the chip of the air flow sensor due to the countercurrent of oil vapor when the engine is stopped during driving of the vehicle, thereby resulting in the occurrence of a trouble.